Podcast Episode 24: Topical Antibiotics

My name is Professor Barbara Conway and I am Head of Pharmacy at the University of Huddersfield in the UK and I'm a registered pharmacist. My research expertise is in formulation and drug delivery and I've for many years worked in the area of improving delivery of drugs into the skin, making sure the drugs get to the right side of action at the right levels needed. With respect to wound care, a pharmacist's role can range from providing first aid, identifying and prescribing for different wound types, to providing education and support to those living with chronic wounds and associated conditions. I've been asked to prepare a short summary for you and best practice with respect to topical antibiotics, what the evidence is for it, and also what alternatives to topical antibiotics are out there and what is their evidence. I think I have to start with stark warning summaries about antimicrobial resistance or AMR. So, antimicrobial resistance is a significant threat to health and human development worldwide. Antibiotic consumption has been clearly shown to contribute to the selection and spread of drug-resistant microorganisms. There's no doubt that antibiotics are one of the most vital discoveries in human history and their use has saved a huge number of lives from what were once lethal infections. but, and it is a big but, the inappropriate use and overuse of antibiotics has played a role in the development of this antimicrobial resistance. This, together with the lack of synthesis of new antibiotics, is a significant challenge to worldwide healthcare, causing morbidity and increased cost of therapy and days of treatment. Multidrug-resistant bacteria have increased the number and costs of hospital stays. One One initiative to curb the threat posed by antimicrobial resistance is the development of antimicrobial stewardship or AMS programs. These educate healthcare workers and control the prescribing and targeting of antimicrobials in order to reduce the likelihood of resistance. Antimicrobial stewardship programs are an essential strategy to combat antimicrobial resistance and they represent a key strategy in promoting responsible antimicrobial use. In some countries, antibiotics are often used as a substitute for basic public health. When formal primary care is missing, patients can obtain antibiotics from pharmacists or lay providers and the responsibility to tackle this growing problem lies with all of us, healthcare practitioners, patients and the public. So back to the topical antibiotic question. The number of clinical scenarios requiring topical antibiotics is actually quite small. In the community, many patients have skin and soft tissue infections that are relatively minor such as scrapes, scratches or mild folliculitis. Pathophysiology of skin and soft tissue infections is related to an interruption in the balance between the immune barrier of the host and the pathogenicity of the microbial population that's colonizing the human skin. So for example, cellulitis is caused by pathogens disrupting skin integrity and it's more prevalent in patients with comorbidities. The outer layers of the skin serve as a barrier to protect us, and disruption of these protective cutaneous layers can be caused by chemical and physical impacts such as ulceration, trauma, bites, surgical wounds, thermal injury or previous inflammation. The management of skin and soft tissue infections often depends on the relative severity and there's always going to be a balance to be had. Uncomplicated skin and soft tissue injuries located in superficial layers typically can be controlled with a topical antimicrobial agent, heat packs or minor incision and wound exudate draining. These type of infections do not usually require antibiotic treatment as they will generally improve with good skin hygiene measures such as cleaning and covering the lesion. A prescription for a topical antiseptic rather than a topical antibiotic could be a pragmatic next step if hygiene interventions are not sufficient, although guidance on the use of antiseptics does vary and there's a relative lack of evidence for their effectiveness. More complicated cases with the involvement of deeper layers with high risk factors will often require systemic antibiotic therapy and even potentially hospital administration. With regards to the emergence of resistant bacteria and antimicrobial stewardship, there is an overall drive to reduce any unnecessary and inappropriate use of antibiotics. Antiseptics have a broad spectrum of antimicrobial activity alongside varying inhibitory mechanisms and so are a potential alternative to topical antibiotics in the treatment of minor skin infections. So although the safety and clinical effectiveness of many antiseptic agents has not been widely demonstrated so far, they do pose potential benefits in the prevention of infections and wounds and are therefore still commonly recommended during pre and per-operative processes which are documented in many global practical guidelines. If a patient does have an infection that requires antibiotic treatment, for example, they may have extensive infection or systemic symptoms or comorbidities that place them at higher risk of infection or poor healing. In most cases, an oral antibiotic rather than a topical antibiotic should be prescribed. So due to increasing resistance, infectious disease experts recommend that topical antibiotics should have a very limited role in clinical practice. There are two main areas where they do have a role. So for example, as a second line option for those with localized impetigo, for example, less than three lesions, if first line management with hygiene measures and topical antibiotics haven't resolved the issue. after about five to seven days, if there hasn't been an improvement, a topical antibiotic prescribed, so fucidic acid should be used. Mupiricin is reserved for treating MRSA infection and in many cases of impetigo, treatment with an oral antibiotic may actually be more appropriate. The second area where topical antibiotics may have a role is in patients with recurrent skin infections due to staphylococcus aureus infections. They may require nasal decolonization with either fucidic acid or mupiricin once susceptibility is known. If the isolate is resistant to both topical antibiotics or there is an active infection, then it may be better to use oral antibiotics. In cases where topical antibiotics are prescribed, the patient must be instructed to use the medicine for up to seven days only and then to discard the tube after that time. So some Some patients may save an unfinished tube as a go-to sort of first aid measure for household members and other people and this really needs to be actively discouraged. Wound healing is a complex process but in healthy individuals it should follow the stages of normal wound healing in an automated fashion and there are four main processes, haemostasis, inflammation, proliferation and maturation. However, there are local and systemic factors that can delay or disrupt these phases and therefore complications can develop. Certain chronic illnesses such as diabetes or Raynaud's disease, heart disease and rheumatoid arthritis and even ageing can make the skin more vulnerable to damage and slower to repair. Minor wounds wounds will normally heal within a couple of weeks, but complicated wounds heal much more slowly. So in broad terms, a wound can be considered chronic or hard to heal if it fails to heal with standard therapy in an orderly and timely manner. So more specifically, a chronic or hard to heal wound can be defined as a wound that has not healed in 12 weeks or if the wound has not improved or not reduced an area by 40% in four weeks of standard care following an appropriate treatment pathway. The time concept is well-established in wound care. It was originally developed by Schultz in 2003, and it provides a structured framework for wound assessment. And the key is around recognising early signs of infections in such wounds. Dressings impregnated with topical antimicrobials should be saved for infected wounds or wounds at high risk of infection. However, due to the wide range of wound types, dressings and products available, and in some cases a lack of specialist knowledge, many pharmacists do not feel confident providing wound care advice. A surgical site infection, for example, is a surgical wound with local signs and symptoms of infection such as heat, redness, pain, swelling, and in some more serious cases with systemic signs of fever or a raised white blood cell count. An infection in the surgical wound may prevent healing, causing the wound edges to separate and it could even cause an abscess to form in the deeper tissues. There's limited evidence on the use of topical wound antiseptics before wound closure in order to prevent infection. When NICE, the National Institute for Clinical Excellence in the UK, reviewed the evidence, there was some evidence suggesting that topical poppadom iodine was effective in reducing surgical site infections, but these studies were dated. There is also evidence that topical antiseptics such as iodine and alcohol solution were actually not effective in reducing surgical site infections. Similarly, evidence on topical antibiotics before wound closure was also varied and somewhat dated. Some studies showed that antibiotics such as ampicillin powder reduced the number of surgical site infections, but the evidence for other antibiotics, such as vancomycin, which is actually widely used in cardiac, orthopedic and spine surgery, suggested no reduction in surgical site infections. So NICE concluded that the evidence wasn't clear or current enough to make a recommendation on the use of topical antiseptics and antibiotics before wound closure. So on balance, taking into account concerns about antimicrobial resistance and the potential for multidrug resistance, it was agreed that without any new conclusive evidence the use of intraoperative topical antibiotics and antiseptics should be stopped. So in practice although the use of topical antiseptics and antibiotics before wound closure may vary, in the UK the NICE guidelines are to limit their used to clinical trials only in an effort to reduce their misuse in practice and encourage research in this area. A useful document for dressing selection and wound care more generally for pharmacy teams is published by Wounds UK. Our aims when we were putting this document together was to inform pharmacy colleagues about the underpinning principles of best practice and also include the latest evidence base in wound care and dressing selection. It would also allow pharmacists to educate other clinicians about the role that pharmacy teams can play in wound care and this guidance should hopefully assist pharmacy teams to manage wounds and select appropriate dressings with confidence. As always, the overall aim is to improve the clinical outcomes for the patient. Before I finish, I just wanted to specifically mention the topical treatment of boils. The majority of boils are caused by Staphylococcus aureus and are usually best treated with a surgical or Lansing procedure. Not every antibiotic is going to work because many varieties of staph over 30 types have become resistant to certain types of antibiotics. So several studies have concluded that taking non-methicillin based systemic antibiotics after incision and draining of the boils can increase the likelihood of full recovery, whereas other studies have actually suggested that systemic antibiotics show no benefit after incision and drainage of a boil. So before prescribing antibiotics for boils, it's suggested to carry out microbial testing to determine the most suitable antibiotic. Thank you very much for listening to my views on topical antibiotics, and it would be remiss of me not to mention our work at the Institute of Skin Integrity and Infection Prevention at the University of Huddersfield. Thank you very much for your attention.